<!DOCTYPE html>
<html lang="en">
<head>
    <meta charset="UTF-8">
    <!-- 可以被替换的内容 -->
    {% block mytitle %}
    <title>网站首页</title>
    {% endblock %}
    <style>
        .header {
            width: 1000px;
            height: 200px;
            background-color: pink;
        }
        .footer {
            width: 1000px;
            height: 100px;
            background-color: orange;
        }
    </style>
</head>
<body>
    <div class="header">头部</div>
    {% block content %}
    <h3>这是首页的内容</h3>
    {% endblock %}
    <div class="footer">底部</div>
</body>
</html>